Q21.9

Congenital malformation of cardiac septum, unspecified

FY2027Chapter 17: Congenital malformations, deformations, chromosomal abnormalities, and genetic disorders/Q20–Q28 Congenital malformations of the circulatory system

BillableComplete code, valid to report

Q21.9 (also written Q219) is a billable ICD-10-CM diagnosis code for congenital malformation of cardiac septum, unspecified. It is part of the FY2027 code set, effective October 1, 2026. It is one of the 17 codes in category Q21 (Congenital malformations of cardiac septa). The Alphabetic Index lists it under 7 entries. Its coding notes include 1 Excludes1 entry and 1 Excludes2 entry.

Guidelines tip

From the FY2027 Official Guidelines. ICD10Ref adds no rules of its own.

Chapter 17 codes can be used for life. Manifestations that are an inherent part of a specifically coded anomaly are not coded separately. A corrected malformation is reported with a personal history code.

Guidelines I.C.17Congenital malformations and genetic disordersRead the official text

Excludes1

Not coded here. The listed conditions generally should not be reported together.

Inherited from Q21 Congenital malformations of cardiac septa
  • acquired cardiac septal defect (I51.0)

Excludes2

Not included here. Both codes may be reported if the patient has both conditions.

Also from chapter/block level (1 note)
Inherited from Chapter 17 Congenital malformations, deformations, chromosomal abnormalities, and genetic disorders
  • inborn errors of metabolism (E70-E88)

Inclusion terms

Conditions classified to this code.

This code
  • Septal (heart) defect NOS

Notes

Also from chapter/block level (1 note)
Inherited from Chapter 17 Congenital malformations, deformations, chromosomal abnormalities, and genetic disorders
  • Codes from this chapter are not for use on maternal records

Alphabetic Index terms

Terms the official Alphabetic Index lists for this code. 7 entries